The invention relates to a clarification method for a beverage liquid, in particular for the production of beer, wine or juices, by applying or using a fast-acting/complexing pectin. In the method the beverage liquid is subjected to clarification after passing through a fermentation stage, said clarification being used to remove haze components from the beverage liquid. In this case the beverage liquid is charged with at least one pectin-containing clarifying agent to increase the subsequent filtration effect. Furthermore, the beverage liquid is supplied to a maturation or storage tank, in which the beverage liquid is stored for a maturation period. Depending on the existing drinks matrix (beer, wine, juices or comparable drinks), particularly with regard to the degree of esterification and amidation, the most suitable pectins to be used as fast-acting/complexing pectins are those which are referred to as Pectino-floc A, B, C etc.
In addition to aroma, taste and colour, the most important qualities of clear drinks (e.g. beer, wine, juices, etc.) include clarity and chemical-physical shelf-life, also referred to as colloidal stability. In order to obtain crystal clear beers, wines or juices, the latter have to be filtered. It is possible to use clarifying agents to increase the filtration effect and shorten the production time of drinks such as beer, wine, fruit juices etc.
The filtered, clear beers, wines and other drinks lose their brightness after a period of time, and after a corresponding storage period an undesirable formation of haze may be observed. Due to the formation of haze the quality of the drinks is generally worsened and the shelf life is reduced. There are many possible reasons for the formation of haze and in principle a distinction is made between biological and non-biological stability. In the case of non-biological stability, which is also referred to as colloidal or chemical-physical stability, chemical and physical reactions are considered to be responsible for the formation of haze, whereas the influence of beer-damaging microorganisms is considered to be the reason in the case of biological stability. Furthermore, non-biological haze is subdivided into cold haze, also known as reversible haze, and permanent haze, which is referred to as irreversible haze.
Cold haze is formed at temperatures between −2° C. and +5° C. and dissolves without residue on heating.
In contrast beers or drinks containing irreversible haze do not clear even at room temperature. Cold haze is considered to be the precursor of irreversible haze and is therefore of particular interest, as by reducing cold haze the formation of irreversible haze is also reduced or prevented.
With regard to the chemical-physical formation of haze in beer and other drinks the interaction between haze-active polyphenols and proteins has been recognised as particularly influential. Therefore, in the drinks industry stabilising agents such as PVPP (polyvinylpolypyrrolidone), bentonite and silica gel are used to remove the haze-active polyphenols or proteins in the production process. More recent research has also shown that specific metal ions are particularly involved in the formation of reversible cold haze. In this case in particular reference is made to the complex formation of metal ions of a specific oxidation stage which are dependent on the temperature and pH with the present polyphenol-protein compounds.
In the pH range of beer (pH 4.2-4.4) in particular oxidised metal ions such as Fe3+/Cu+ are formed after using up the endogenous antioxidant potential by oxidative processes involving the Fenton-Haber-Weiss reaction system and, with the existing polyphenol-protein compounds, produce visible, temperature and pH-dependent complex compounds.
In addition to the clarifying effect of pectic acid described in DE 3614656 C1, which has also occasionally been used in the past for fining wine, WO 2006/032088 A2 describes the use of pectin as a stabiliser in the brewing process. In this connection, in addition to the clarifying effect of pectin the stabilising effect on the colloidal shelf life of beers is highlighted in particular. To explain the stabilising effect and the corresponding increase in the colloidal shelf life different possible mechanisms have been proposed and described with the formation of networks between pectin and Ca2+, Mg2+ ions. The haze-active polyphenols, proteins and carbohydrates are meant to embed themselves into the formed networks and are removed by sedimentation or at the latest during filtration.
According to WO 2006/032088 A2 the pectin used causes a significant colloidal stabilisation effect when added in an aqueous solution of sodium citrate, citric acid and potassium metabisulfite to unfiltered beer during maturation.
In contrast to PVPP and silica gel however, research has not shown a significant stabilisation effect on the colloidal beer stability caused directly by the pectin. This is the case in particular if the pectin is simply added to the unfiltrate dissolved in an aqueous solution or buffering solution (i.e. without sodium citrate, citric acid and potassium metabisulfite) according to the teaching of WO 2006/032088 A2 during maturation. Rather all of the results indicate that the delayed formation of haze described in said prior art and the associated higher colloidal beer stability are not caused by the pectin as such, but are the result of the indirect addition of SO2 and citric acid by means of the predetermined pectin solution with the use of potassium metabisulfite or sodium citrate/citric acid.
In Germany the direct addition of sulphur dioxide to beers brewed according to the German purity law is not permissible. Sulphur dioxide is an important antioxidant in beer and other drinks and may be added to increase the oxidative beer (drink) stability. The formation of haze in beers relative to the storage period is directly associated with oxidative processes and the oxidative beer stability. The connection between oxidative and colloidal beer stability has long been known and was recently verified by relevant research considering the endogenous antioxidative potential of beers (drinks). On the basis of the described connections, the colloidal beer stabilisation described in the prior art is not a result of the added pectin but is achieved by the addition of SO2 and citric acid. In this way the contents of beer involved in the formation of haze (e.g. metal ions) can be complexed (e.g. citric acid) and the formation of haze caused by oxidation can be delayed (mainly addition of SO2).
In contrast to the negative evidence as a stabilising agent, the clarifying effect of the pectin in the production process was clearly evident regardless of the SO2 content in all of the research work. In corresponding laboratory trials it was possible with different types of pectin to achieve a good clarification effect during beer maturation and to reduce the filtration times or significantly increase the filtration effect.
FIG. 1 shows a filtration line V1 after clarification using 80 ppm pectin B and a control line K in the absence of pectin. The lines show respectively the mass G in grams of the held-back material over time t in seconds. The filtration is performed at 0.5 bar, 0° C. and 0.45 pm.
In larger scale production however, unlike the conditions described in the prior art, there were huge difficulties related to handling. The sedimentation of a pectin flake described in the prior art could not be achieved because of the flow conditions during beer maturation or could only be achieved rarely in application. This is mainly because of the flow conditions and the very light pectin agglomerates (pectin flakes) which are held in suspension by the slightest vibration or flows. On this basis it is difficult to draw off a more clarified beer in the upper maturation tank area for accelerated filtration and to perform filtering without corresponding losses of beer.
Additional filtration trials have shown that the pectin agglomerates held in suspension are only suitable to a limited degree or are not at all suitable for accelerating the filtration after maturation. This is probably due to the fact that the network formed by the pectin in the described procedure over time in the maturation or storage tank goes back into the solution or breaks up and the partially dissolved pectin reduces the filtration effect.
The procedure described in the prior art is also only suitable to a limited extent for handling pectin easily and above all using it economically as a clarifying agent in beer production, i.e. pectin is not suitable as a stabilising agent and in the given procedure is only suitable to a limited degree as a clarifying agent in the brewing process.
Furthermore, for a number of years gallotannins have been used in the brewing industry for colloidal stabilisation and for avoiding the gushing effects in drinks (gushing: excessive spontaneous foaming of drinks after opening a bottle). The functional principle is based on the fact that the gallotannins bind to the existing haze-active or active gushing protein fractions and then the precipitations formed can be separated (e.g. filtration). When using gallotannins to reduce the gushing potential of drinks use is additionally made of the fact that active gushing and prooxidatively-acting metal ions, in particular Fe, are present in complexed form in the gallotannin-protein compounds formed and can be removed by the formed precipitations.